Before using any paid software for OST to PST conversion, you should try few easy manual tricks. They don't require any 3rd party tool or any other cost. All you need to use is MS Outlook client, that's it. It has few built-in features which you can use there to transfer mailbox content from OST files to new PST files. The features which you can use here are: Import, Export to a new PST file, Move the items to a new PST file and Drag & Drop. Refer to this blog post to know how to use these features: Convert OST to PST Format using 3 Easy Manual Tricks | N. Sem's Blog

Before you can use any of the manual tricks shared in the above blog post, make sure:

You are using the same computer system on which your OST files are originally created.

Your Outlook profile is connected with MS Exchange Server.

And most importantly, the OST files are valid, i.e. not corrupt.

If you can't use any of the manual tricks shared in the above blog post, you should use a professional converter utility. You can download OST Recovery software that works as a recovery cum converter utility. The best part of this software is that it supports corrupt OST files as well. Via this software, you can extract your mailbox content from OST files and then save them into new PST files.

I want give reference of Atom TechSoft ost recovery tool here because i used it for the recovery of ms outlook 2016 ost file ,it did amazingly .So from then to now i share this tool to everyone whom required .

Use this first class ost repair software tool to recover ost file .This software easily recover ost backup with full data including each folder present in ost file such as inbox,calendar ,notes,contacts ,etc .

It support all version of ms outlook ost file that are ost 2016,ost 2013,ost 2010,ost 2007,ost 2003,ost 2002,ost 2000 ,etc .You are free to perform any kind of ost recovery and ost to pst conversion with this Atom TechSoft ost repair application .

For more help ask question to data recovery experts :- support@atomtechsoft.com

If your OST file gets corrupted and can't access in MS Outlook. In this situation you are searching an easy and reliable solution for repairing corrupted file. There are many tools available on the web, that can effectively do the repairing and conversion process. I also suggest you can read this blog post and know more about how to repair corrupted OST file and convert the data into PST, MSG, EML or HTML format. The recommended blog provides freeway conversion steps, visit this blog here:- http://migrateemails.com/2016/01/23/convert-ost-to-pst-format/